From fb63de756870a3dd875a6ae57ab8c018b4500c23 Mon Sep 17 00:00:00 2001
From: InsanusMokrassar <ovsyannikov.alexey95@gmail.com>
Date: Wed, 17 Nov 2021 14:22:45 +0600
Subject: [PATCH] intersect

---
 CHANGELOG.md                                  |  3 +++
 .../micro_utils/common/RangeIntersection.kt   | 19 +++++++++++++++++++
 pagination/common/build.gradle                | 10 ++++++++++
 .../inmo/micro_utils/pagination/Pagination.kt |  7 +++++++
 4 files changed, 39 insertions(+)
 create mode 100644 common/src/commonMain/kotlin/dev/inmo/micro_utils/common/RangeIntersection.kt

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5b016dd9dab..410ddfff15d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,8 +2,11 @@
 
 ## 0.8.3
 
+* `Common`:
+    * Ranges intersection functionality
 * `Pagination`:
     * `Pagination` now extends `ClosedRange<Int>`
+    * `Pagination` intersection functionality
 
 ## 0.8.2
 
diff --git a/common/src/commonMain/kotlin/dev/inmo/micro_utils/common/RangeIntersection.kt b/common/src/commonMain/kotlin/dev/inmo/micro_utils/common/RangeIntersection.kt
new file mode 100644
index 00000000000..e8bcf5a5750
--- /dev/null
+++ b/common/src/commonMain/kotlin/dev/inmo/micro_utils/common/RangeIntersection.kt
@@ -0,0 +1,19 @@
+package dev.inmo.micro_utils.common
+
+fun <T : Comparable<T>> ClosedRange<T>.intersect(other: ClosedRange<T>): Pair<T, T>? = when {
+    start == other.start && endInclusive == other.endInclusive -> start to endInclusive
+    start > other.endInclusive || other.start > endInclusive -> null
+    else -> maxOf(start, other.start) to minOf(endInclusive, other.endInclusive)
+}
+
+fun IntRange.intersect(
+    other: IntRange
+): IntRange? = (this as ClosedRange<Int>).intersect(other as ClosedRange<Int>) ?.let {
+    it.first .. it.second
+}
+
+fun LongRange.intersect(
+    other: LongRange
+): LongRange? = (this as ClosedRange<Long>).intersect(other as ClosedRange<Long>) ?.let {
+    it.first .. it.second
+}
diff --git a/pagination/common/build.gradle b/pagination/common/build.gradle
index 7c54502f100..082ce99346a 100644
--- a/pagination/common/build.gradle
+++ b/pagination/common/build.gradle
@@ -5,3 +5,13 @@ plugins {
 }
 
 apply from: "$mppProjectWithSerializationPresetPath"
+
+kotlin {
+    sourceSets {
+        commonMain {
+            dependencies {
+                api project(":micro_utils.common")
+            }
+        }
+    }
+}
diff --git a/pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/Pagination.kt b/pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/Pagination.kt
index 5afd2b1461e..b20a778af2f 100644
--- a/pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/Pagination.kt
+++ b/pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/Pagination.kt
@@ -1,5 +1,6 @@
 package dev.inmo.micro_utils.pagination
 
+import dev.inmo.micro_utils.common.intersect
 import kotlin.math.ceil
 import kotlin.math.floor
 
@@ -27,6 +28,12 @@ interface Pagination : ClosedRange<Int> {
         get() = lastIndex
 }
 
+fun Pagination.intersect(
+    other: Pagination
+): Pagination? = (this as ClosedRange<Int>).intersect(other as ClosedRange<Int>) ?.let {
+    PaginationByIndexes(it.first, it.second)
+}
+
 /**
  * Logical shortcut for comparison that page is 0
  */